Electromagnetic shielding structure of power module

Abstract

This utility model relates to the field of power module technology, specifically to an electromagnetic shielding structure for a power module. It includes a power module, a protection module, a reverse connection protection module, and a filter module, all electrically connected in sequence. The protection module provides overcurrent protection, surge protection, and polarity protection. The reverse connection protection module cuts off the circuit in case of reverse connection. The filter module filters out noise. In this utility model, the protection module offers multiple protections: the fuse RF blows when the current is abnormal, providing overcurrent protection; the gas discharge tube (GDT) and transient voltage regulator (TVS) work together to absorb surge voltage; diodes D1 and D2 provide polarity protection; in the reverse connection protection module, the PMOS transistor is triggered to turn off by a voltage divider between resistors R3 and R4 after detecting a reverse connection signal, preventing reverse current surges; and the filter module filters out noise, improving safety and enhancing practicality.

Description

Technical Field

[0001] This utility model relates to the field of power module technology, and more specifically, to the electromagnetic shielding structure of a power module. Background Technology

[0002] A power module is an integrated electronic device mainly used for the conversion, control and distribution of high-power or high-voltage electrical energy. It achieves efficient and stable power processing by encapsulating multiple semiconductor devices with protection circuits and heat dissipation structures. Power modules are widely used in industrial control, new energy equipment and other fields.

[0003] Existing power modules have some problems in practical applications. Traditional power modules usually only have a single overcurrent or surge protection function, and cannot cope with complex faults such as overcurrent, overvoltage and reverse polarity at the same time. Moreover, the modules are susceptible to external electromagnetic interference when they are working, and the output signal is often mixed with high-frequency noise, which affects the stability of the downstream equipment. If the power supply polarity is reversed during installation or maintenance, it may cause the module to burn out or the system to fail. Utility Model Content

[0004] The purpose of this invention is to provide an electromagnetic shielding structure for power modules to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: The electromagnetic shielding structure of the power module includes a power module, a protection module, a reverse connection protection module, and a filter module connected in sequence. The protection module is used for overcurrent protection, surge protection, and polarity protection. The reverse connection protection module is used to cut off the circuit when reversed. The filter module is used to filter out noise.

[0006] Preferably, the protection module includes a fuse RF, a gas discharge tube GDT, an inductor L1, a diode D1, a diode D2, and a transient diode TVS; The first terminal of the fuse RF is connected to the positive output terminal of the power module, the second terminal of the fuse RF is connected to the first terminal of the inductor L1, the first terminal of the gas discharge tube GDT is connected to the second terminal of the fuse RF, the second terminal of the gas discharge tube GDT is connected to the reverse output terminal of the power module, the negative terminal of diode D1 is connected to the second terminal of inductor L1, the positive terminal of diode D1 is connected to the first terminal of transient diode TVS, the positive terminal of diode D2 is connected to the second terminal of inductor L1, the negative terminal of diode D2 is connected to the first terminal of transient diode TVS, and the second terminal of transient diode TVS is connected to the reverse output terminal of the power module.

[0007] Preferably, the reverse connection protection module includes a PMOS transistor, resistor R3, resistor R4, and diode D3; The drain of the PMOS transistor is connected to the second terminal of inductor L1, the source of the PMOS transistor is connected to the first terminal of resistor R3, the second terminal of resistor R3 is connected to the gate of the PMOS transistor, the first terminal of resistor R4 is connected to the gate of the PMOS transistor, the second terminal of resistor R4 is connected to the second terminal of transient diode TVS, the anode of diode D3 is connected to the second terminal of resistor R3, and the cathode of diode D3 is connected to the first terminal of resistor R3.

[0008] Preferably, the filtering module includes an inductor L2, a capacitor C1, and a capacitor C2; The first input terminal of inductor L2 is connected to the negative terminal of diode D3, the second input terminal of inductor L2 is connected to the second terminal of resistor R4, the first terminal of capacitor C1 is connected to the first output terminal of inductor L2, the second terminal of capacitor C1 is connected to the second output terminal of inductor L2, the first terminal of capacitor C2 is connected to the first terminal of capacitor C1, and the second terminal of capacitor C2 is connected to the second terminal of capacitor C1.

[0009] Compared with the prior art, the beneficial effects of this utility model are: This utility model features multiple protection modules. The fuse RF blows when the current is abnormal, providing overcurrent protection. The gas discharge tube (GDT) and transient diode (TVS) work together to absorb surge voltage. Diodes D1 and D2 provide polarity protection. In the reverse connection protection module, the PMOS transistor is triggered to turn off by voltage division through resistors R3 and R4 after detecting a reverse connection signal, preventing reverse current surges. The filter module filters out noise, improving safety and enhancing practicality. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of the utility model; Figure 2 This is a circuit diagram of the protection module, reverse connection protection module, and filtering module in the utility model. In the picture: 1. Power module; 2. Protection module; 3. Reverse connection protection module; 4. Filtering module. Detailed Implementation

[0011] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Please see Figure 1 and Figure 2 The present invention provides the following technical solution: The electromagnetic shielding structure of the power module includes a power module 1, a protection module 2, a reverse connection protection module 3, and a filter module 4 connected in sequence. The protection module 2 is used for overcurrent protection, surge protection, and polarity protection. The reverse connection protection module 3 is used to cut off the circuit when reversed. The filter module 4 is used to filter out noise. The power module 1 is controlled by an external device, which can be a microprocessor. The power module 1, protection module 2, reverse connection protection module 3, and filter module 4 are arranged in a partitioned layout to reduce the cross-interference between high current paths and sensitive signal lines. The grounding terminals of all modules are connected to a unified grounding point through a low-impedance path to avoid noise introduced by ground loops.

[0012] In this embodiment, the protection module 2 includes a fuse RF, a gas discharge tube GDT, an inductor L1, a diode D1, a diode D2, and a transient diode TVS; The first terminal of fuse RF is connected to the positive output terminal of power module 1, and the second terminal of fuse RF is connected to the first terminal of inductor L1. The first terminal of gas discharge tube GDT is connected to the second terminal of fuse RF, and the second terminal of gas discharge tube GDT is connected to the reverse output terminal of power module 1. The cathode of diode D1 is connected to the second terminal of inductor L1, and the anode of diode D1 is connected to the first terminal of transient diode TVS. The anode of diode D2 is connected to the second terminal of inductor L1, and the cathode of diode D2 is connected to the first terminal of transient diode TVS. The second terminal of transient diode TVS is connected to the reverse output terminal of power module 1. When the output current of power module 1 increases abnormally, fuse RF connected in series at the positive output terminal will melt due to overheating, quickly cutting off the circuit and preventing damage to downstream circuits due to overcurrent. The DT and the transient voltage regulator (TVS) form a dual protection system. The gas discharge tube (GDT) absorbs high-energy surge voltage through gas ionization, while the TVS suppresses low-energy transient overvoltage through fast clamping characteristics. The two work together to cover a wide range of surge protection. Diodes D1 and D2 form a polarity protection circuit. When the input polarity is correct, diode D1 conducts in the forward direction and diode D2 is reverse-biased and cut off, allowing normal signal transmission. If the input polarity is accidentally reversed, diode D2 conducts in the forward direction and bypasses the reverse voltage, while diode D1 is reverse-biased and cut off the reverse current, preventing damage to power module 1. Inductor L1 is connected in series in the circuit to suppress high-frequency noise and transient current surges, further stabilizing the current output.

[0013] Specifically, the reverse connection protection module 3 includes a PMOS transistor, resistor R3, resistor R4, and diode D3; The drain of the PMOS transistor is connected to the second terminal of inductor L1, the source of the PMOS transistor is connected to the first terminal of resistor R3, the second terminal of resistor R3 is connected to the gate of the PMOS transistor, the first terminal of resistor R4 is connected to the gate of the PMOS transistor, the second terminal of resistor R4 is connected to the second terminal of transient diode TVS, the anode of diode D3 is connected to the second terminal of resistor R3, and the cathode of diode D3 is connected to the first terminal of resistor R3. When the polarity is reversed, the source voltage of the PMOS transistor is higher than the drain voltage. At this time, resistors R3 and R4 form a voltage divider network, making the gate voltage of the PMOS transistor lower than the threshold voltage, and the PMOS transistor is quickly turned off. After the PMOS transistor is turned off, its drain and source present a high impedance state, completely cutting off the reverse current path and preventing the reverse current from impacting power module 1 and the back-end circuit. Diode D3 is connected in parallel across resistor R3. During normal operation, it is reverse cut off and does not affect the voltage divider network. When the PMOS transistor is turned off, diode D3 can provide a freewheeling path for the residual current of inductor L1, avoiding voltage spikes.

[0014] Furthermore, the filter module 4 includes an inductor L2, a capacitor C1, and a capacitor C2; The first input terminal of inductor L2 is connected to the negative terminal of diode D3, and the second input terminal of inductor L2 is connected to the second terminal of resistor R4. The first terminal of capacitor C1 is connected to the first output terminal of inductor L2, and the second terminal of capacitor C1 is connected to the second output terminal of inductor L2. The first terminal of capacitor C2 is connected to the first terminal of capacitor C1, and the second terminal of capacitor C2 is connected to the second terminal of capacitor C1. When inductor L2 is designed as a common-mode inductor, it can further suppress common-mode interference and reduce the coupling effect of electromagnetic radiation on downstream equipment. Capacitors C1 and C2 are used in parallel. C1 is a large-capacity electrolytic capacitor used to filter out low-frequency ripple; C2 is a small-capacity ceramic capacitor used to absorb high-frequency noise. The two complement each other to broaden the filtering frequency band and improve the purity of the output signal. In use, the electromagnetic shielding structure of the power module of this utility model first outputs electrical energy from the power module 1, which then undergoes multiple protections through the protection module 2. The fuse RF melts and cuts off the circuit in case of overcurrent. The gas discharge tube (GDT) and transient diode (TVS) work together to absorb surge voltage. Diodes D1 and D2 prevent reverse input through polarity switching. Subsequently, the signal enters the reverse connection protection module 3. In case of reverse connection, the PMOS transistor is triggered to turn off through resistor voltage division, completely blocking the reverse current path. At the same time, diode D3 provides a freewheeling path for residual current. Finally, the electrical energy passes through the filter module 4 to filter out high-frequency noise and low-frequency ripple, ensuring a pure and stable output signal. Each module works in sequence and in concert to eliminate overcurrent, surge, reverse connection, and electromagnetic interference step by step, ultimately achieving safe and efficient power output.

[0015] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. The electromagnetic shielding structure of a power module, characterized in that: The device includes a power module (1), a protection module (2), a reverse connection protection module (3), and a filter module (4) connected in sequence. The protection module (2) is used for overcurrent protection, surge protection, and polarity protection. The reverse connection protection module (3) is used to cut off the circuit when reversed. The filter module (4) is used to filter out noise.

2. The electromagnetic shielding structure of the power module according to claim 1, characterized in that: The protection module (2) includes a fuse RF, a gas discharge tube GDT, an inductor L1, a diode D1, a diode D2, and a transient diode TVS; The first terminal of the fuse RF is connected to the positive output terminal of the power module (1), the second terminal of the fuse RF is connected to the first terminal of the inductor L1, the first terminal of the gas discharge tube GDT is connected to the second terminal of the fuse RF, the second terminal of the gas discharge tube GDT is connected to the reverse output terminal of the power module (1), the negative terminal of the diode D1 is connected to the second terminal of the inductor L1, the positive terminal of the diode D1 is connected to the first terminal of the transient diode TVS, the positive terminal of the diode D2 is connected to the second terminal of the inductor L1, the negative terminal of the diode D2 is connected to the first terminal of the transient diode TVS, and the second terminal of the transient diode TVS is connected to the reverse output terminal of the power module (1).

3. The electromagnetic shielding structure of the power module according to claim 2, characterized in that: The reverse connection protection module (3) includes a PMOS transistor, resistor R3, resistor R4, and diode D3; The drain of the PMOS transistor is connected to the second terminal of inductor L1, the source of the PMOS transistor is connected to the first terminal of resistor R3, the second terminal of resistor R3 is connected to the gate of the PMOS transistor, the first terminal of resistor R4 is connected to the gate of the PMOS transistor, the second terminal of resistor R4 is connected to the second terminal of transient diode TVS, the anode of diode D3 is connected to the second terminal of resistor R3, and the cathode of diode D3 is connected to the first terminal of resistor R3.

4. The electromagnetic shielding structure of the power module according to claim 3, characterized in that: The filtering module (4) includes an inductor L2, a capacitor C1, and a capacitor C2; The first input terminal of inductor L2 is connected to the negative terminal of diode D3, the second input terminal of inductor L2 is connected to the second terminal of resistor R4, the first terminal of capacitor C1 is connected to the first output terminal of inductor L2, the second terminal of capacitor C1 is connected to the second output terminal of inductor L2, the first terminal of capacitor C2 is connected to the first terminal of capacitor C1, and the second terminal of capacitor C2 is connected to the second terminal of capacitor C1.

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